1520s, "sounding together tunefully," from French harmonieux (14c.), from harmonie (see harmony). In nonmusical use from 1630s. Related: Harmoniously; harmoniousness.
1560s, "relating to music," from Latin harmonicus, from Greek harmonikos "harmonic, musical, skilled in music," from harmonia (see harmony). From 1660s as "tuneful, harmonious; relating to harmony" (earlier as armonical "tuneful, harmonious," c. 1500). The noun, short for harmonic tone, is recorded from 1777. Related: Harmonically.
"loving harmony or music," 1813 (in the name of a society founded in London for the promotion of instrumental music), from French philharmonique (1739), from Italian filarmonico, literally "loving harmony," from Greek philos "loving" (see philo-) + ta harmonika "theory of harmony, music," from neuter plural of harmonikos (see harmonic). The Society name was taken up in the names of many symphony orchestras.